Spaceflight Insider

Our SpaceFlight Heritage: Apollo 13 – NASA’s successful failure

David Darling

April 17th, 2016

On this date, April 17, 1970, the crew of Apollo 13 safely returned to Earth. Image Credit: James Vaughan / SpaceFlight Insider

KENNEDY SPACE CENTER, Fla. — It was the most harrowing adventure of the Apollo era, Apollo 13. It also served as one of the most critical tests for NASA after the Apollo 1 fire. Luckily for the crew, the team at NASA’s Mission Control Center came through with flying colors and it came to its conclusion on this date in space flight history – April 17, 1970.

The seventh crewed mission of the Apollo Project Apollo 13 is one of the few Apollo missions that has made its way into the public’s collective consciousness, likely because it was the one that nearly ended in disaster.

Apollo 13 was launched on schedule at 13:13 p.m. Houston time (CDT), on April 11, 1970, from Launch Complex 39A at NASA’s Kennedy Space Center located in Florida.

On April 13, while en route to the Moon, an oxygen tank in the Service Module (SM) exploded. The crew got home safely thanks to the consumables and propulsion system of the Lunar Module (LM), and the ingenuity of ground controllers in improvising LM lifeboat procedures.

The S-IVB stage that boosted the mission into translunar trajectory was delivered to Kennedy Space Center on June 13, 1969 – a Friday. Three days before launch, Swigert replaced Thomas Mattingly as Command Module (CM) pilot because of Mattingly’s exposure to German measles (the only preflight substitution of this kind at that time).

Following liftoff, the second stage S-II booster’s center engine cut off approximately 132 seconds early. To compensate, the four remaining S-II engines burned for an extra 34 seconds, and the S-IVB third stage remained active for an additional 9 seconds. For a while, the flight continued according to plan. For the first time, the S-IVB third stage was fired on a lunar trajectory following spacecraft separation and struck the Moon, so that the resulting “moonquake” could be measured, at a point about 85 miles (137 km) from the seismometer planted by the Apollo 12 astronauts. Unfortunately, the S-IVB would be the only part of Apollo 13 to reach the lunar surface.

About 56 hours after liftoff and more than halfway to the Moon, a spark and resulting fire ruptured the Number Two Oxygen Tank in the Service Module section of the CSM causing a violent explosion. This resulted in the loss of all fuel-cell-generated electricity which led to many other complications, including a complete loss of oxygen and water supply from the CSM.

Image Credit: NASA

The mission was immediately aborted and all efforts shifted to the safe return of the crew. The CSM was powered down, and the crew moved to the LM for the bulk of the return flight. Not wishing to risk complicated maneuvers to turn the spacecraft around, NASA directed Apollo 13 to proceed around the Moon. Virtually all spacecraft systems were shut down to conserve power. The crew squeezed into the LM which was designed to support two astronauts for about 50 hours but now needed to support all three astronauts for four days. The crew endured temperatures at or below freezing for the bulk of the return flight as well as other hardships, including water rationed to 170 grams per astronaut per day.

After circling the Moon once, the LM descent engine was fired twice to establish a fast return path to Earth. Nearing Earth, Swigert returned to the CSM to power up the craft using onboard batteries. Engineers were not certain that power could be restored due to the low temperatures encountered during the flight. However, sufficient power was restored without difficulty.

Swigert jettisoned the SM while Lovell and Haise remained aboard the LM. Following jettison, the crew viewed and took dramatic pictures of the explosion’s aftermath: an entire side of the SM had been blown out. Eventually, Lovell and Haise joined Swigert on the CM; the LM, which had successfully served as a lifeboat, was jettisoned, and the CM re-entered Earth’s atmosphere. Under such circumstances, no one knew if the CM would come in at the proper angle to avoid burning up in or skipping off of the atmosphere.

As was the case in all previous U.S. crewed spaceflights, there was a communications blackout of several minutes during re-entry. However, as had been the case with so many other aspects of Apollo 13, this too had more drama than was anticipated. The blackout lasted six minutes – about one minute and 27 seconds longer than had been anticipated. Then, to the cheers of an anxious world, Apollo 13 splashed down within sight of the recovery team and the crew were rescued about one hour later.

This article originally appeared on The Worlds of David Darling and can be viewed here: Apollo 13

Dr. David Darling is an astronomer and author of numerous books, including We Are Not Alone, Megacatastrophes, The Complete Book of Spaceflight, and his latest, The Rocket Man. His website, The Worlds of David Darling, is one of the largest and most visited science resources on the Internet.
Darling is a renaissance man, he is a musician, noted author and journalist and serves as our science writer. Darling provides The Spaceflight Group with articles detailing what he knows best - space exploration.